2.15.2010

Fine-grain, useful mapping


Joseph O. Holmes, 20x200

[super wonky post follows]

There were many good sessions at the Active Living Research (ALR) conference, but my favorite one was the session on micro-scale GIS, based on work out of the Urban Form Lab at the University of Washington in Seattle, run by Anne Vernez Moudon (who also moderated the panel I was on) and Chanam Lee. That intersection of anthropology (specifically, collecting observations on human behavior) plus the mapping of data in local-space always gets me.

The methodology she showed us was of particular interest because it employs sophisticated tools for data that some of us working at the local level collect all the time - desire lines, most popular access points, local walking routes, local destinations, local transit use, micro-land use, etc. We do this by hand; lacking the GIS tool, we have literally hand-drawn layers of collected input on top of each other. Very time-consuming and static. Still, it's done because it's really useful for understanding neighborhood-wide transit use and the use of amenities to encourage walkability, for example.

Scale is all so important when it comes to understanding how to make tweaks to systems. An appropriately small scale at 20/50/100 feet reveals useful marks that can be easily lost when you go up to 500 feet. An example she showed us was on local transit use for Seattle. At a transit system level, the neighborhood was well-served by transit stops - an even distribution of bus stops, it appears. When individual self-identified use was mapped at a smaller scale, it became clear that one bus stop was preferred against all others. This stop is essentially the transit heart of the neighborhood. Should more resources go to reinforce this stop? What made the other stops less desirable? This mapping exercise allowed the transit agency to see more about use on the transit line than would be readily available with conventional data sets, though I'm no expert.

Perhaps the concept is well understood in the theory of urban planning, but this micro-level of spatial analysis is rarely applied to real projects going on now. It would be fun to see Open Street Map do a Micro-Street Map version allowing for local built environment condition mapping, maybe as a companion to Open Route Service. Professor Moudon, maybe you should donate your data?

(I tried to find the presentation online but it's not up yet; I'll update this post when it is).

It's not just the mapping that makes this work. The lab makes some good-looking maps too, adding to the overall persuasiveness of the work.

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